Heparin-coated polyacrylonitrile membrane versus regional citrate anticoagulation: A prospective randomized study of 2 anticoagulation strategies in patients at risk of bleeding

Background: Hemodialysis requires anticoagulation to prevent clotting of the extracorporeal circuit. Systemic anticoagulation with heparin is contraindicated in patients at high risk of bleeding. In these patients, regional citrate anticoagulation (RCA), with either calcium-free (RCA-Ca0) or calcium-containing dialysate (RCA-Ca3.0), and heparin-coated membranes (1.3 m(2); AN69ST; Nephral 300ST, Gambro-Hospal, Meyzieu, France) may represent valid alternatives. Methods: To compare the efficacy and safety of these regional anticoagulation modalities, we performed a prospective randomized trial including 33 hemodialysis patients at high risk of bleeding. Regional anticoagulation was achieved by means of either AN69ST (11 patients, 31 sessions), RCA-Ca0 (11 patients, 32 sessions), or RCA-Ca3.0 (11 patients, 30 sessions). Patients assigned to RCA were dialyzed using a polysulfone membrane (1.3 m(2); F60; Fresenius Medical Care, Bad Homburg, Germany). Scheduled dialysis time was 4 hours. At the end of each dialysis session, the dialyzer was inspected for visible signs of thrombus formation and scored semiquantitatively (0, no clotting, to 4, severe clotting). Solute clearances were monitored at the second and fourth treatment hour as a parameter of subclinical clotting of the dialyzer. Results: Clotting phenomena necessitating premature termination of the dialysis session were encountered in 39%, 13%, and 0% using AN69ST, RCA-Ca3.0, and RCA-Ca0, respectively (P < 0.005). All clotting with AN69ST occurred after the second treatment hour. Mean dialyzer clotting scores were 2.7, 1.5, and 1.1, respectively (P < 0.0001). Significantly greater instantaneous urea nitrogen clearances were achieved at 2 hours during RCA compared with AN69ST. Except for clotting phenomena, no adverse events were observed. Conclusion: Citrate provides superior regional anticoagulation compared with AN69ST membranes.